pmpx¶
-
erfa.
pmpx
(rc, dc, pr, pd, px, rv, pmt, pob)[source]¶ Wrapper for ERFA function
eraPmpx
.- Parameters
rc : double array
dc : double array
pr : double array
pd : double array
px : double array
rv : double array
pmt : double array
pob : double array
- Returns
pco : double array
Notes
The ERFA documentation is below.
- - - - - - - - e r a P m p x - - - - - - - - Proper motion and parallax. Given: rc,dc double ICRS RA,Dec at catalog epoch (radians) pr double RA proper motion (radians/year; Note 1) pd double Dec proper motion (radians/year) px double parallax (arcsec) rv double radial velocity (km/s, +ve if receding) pmt double proper motion time interval (SSB, Julian years) pob double[3] SSB to observer vector (au) Returned: pco double[3] coordinate direction (BCRS unit vector) Notes: 1) The proper motion in RA is dRA/dt rather than cos(Dec)*dRA/dt. 2) The proper motion time interval is for when the starlight reaches the solar system barycenter. 3) To avoid the need for iteration, the Roemer effect (i.e. the small annual modulation of the proper motion coming from the changing light time) is applied approximately, using the direction of the star at the catalog epoch. References: 1984 Astronomical Almanac, pp B39-B41. Urban, S. & Seidelmann, P. K. (eds), Explanatory Supplement to the Astronomical Almanac, 3rd ed., University Science Books (2013), Section 7.2. Called: eraPdp scalar product of two p-vectors eraPn decompose p-vector into modulus and direction Copyright (C) 2013-2019, NumFOCUS Foundation. Derived, with permission, from the SOFA library. See notes at end of file.